1. Field of the Invention
The present invention relates to compressors, particularly to those utilized in air conditioning and refrigeration systems, and more particularly to an oil exchanger utilized to effectively remove oil from the crankcase of such compressors, and for the introducing of replacement oils.
2. Background Art
Techniques for the removal of oil, or similar lubricating materials, from the crankcase of internal combustion engines have been known for many years. However, because of the particular problems involved in removing the oil from the crankcase of compressors utilized in air conditioning and refrigeration systems, relatively few techniques have been developed for this particular purpose. More than ever before, effective techniques are required for such removal and replacement of oils in air conditioning and refrigeration compressors, inasmuch as the current oils being utilized are highly subject when exposed to the atmosphere, to the absorption of moisture which tends to dilute the oils, reducing their lubricating efficiency. Any system to be totally effective must be a hermetic or relatively closed system, which prevents the oil from being exposed to the atmosphere.
A background art search directed to the subject matter of this application and conducted in the U.S. Patent and Trademark Office disclosed the following U.S. Letters Patents:
______________________________________ 2,148,807 4,240,523 5,044,469 2,856,026 4,570,458 5,056 623 3,128,844 4,698,983 5,074,380 3,858,686 4,807,674 5,184,944 4,095,672 4,973,235 ______________________________________
None of the patents discovered disclosed an effective apparatus or method for changing the oil from the crankcase of refrigeration or air conditioning compressors. Many of the patents related to the removal of oil from automobile crankcases. The techniques and apparatus related to automobile crankcase oil removal are not appropriate inasmuch as they are not in pressurized systems, such as are found in the compressors for which the present invention is intended.
The only patents related to the removal of oil from compressors, and/or related methods of doing same, are taught by U.S. Pat. Nos. 4,570,458, 4,698,983 and 5,184,944. Of these, only U.S. Pat. No. 5,184,944 is related to the exchanging of oil for drainage, where the crankcase is refilled. U.S. Pat. No. 5,184,944, which issued to Thomas F. Scarfone on Feb. 9, 1993 is related to a method and apparatus for changing lubricating oil in a specially designed rotary compressor, which includes a vertically extending rotor shaft from the top of the case to the bottom, where in the bottom of the case forms the lubricating oil sump. The rotor shaft has a longitudinally extending opening through the shaft which defines a path from the sump to the upper end of the case. Such devices are not of usual design. The particular apparatus and technique enclosed herein is limited by its application to the specialized rotary type compressor with a hollow drive shaft facilitating communication between the oil sump of the compressor with the upper end of the compressor casing.